U.S. patent application number 11/105240 was filed with the patent office on 2005-08-25 for laryngoscope.
This patent application is currently assigned to Western Sydney Area Health Service of Westmead Hospital, Techmin Pty Ltd. Invention is credited to Dey, Philip, Klineberg, Peter, Stokan, Murray.
Application Number | 20050187434 11/105240 |
Document ID | / |
Family ID | 25646617 |
Filed Date | 2005-08-25 |
United States Patent
Application |
20050187434 |
Kind Code |
A1 |
Dey, Philip ; et
al. |
August 25, 2005 |
Laryngoscope
Abstract
A sensing means attachable to a blade (41) of a laryngoscope
(40) comprising a transducer (10) and an indicator means (11). The
transducer comprises at least a layer of a polymeric material (12)
that undergoes a change in resistivity in response to incident
pressure thereon. The change in resistivity is useable by the
indicator means (11) to provide an output at least indicative of
the incident pressure. A laryngoscope (40) having a LED-type light
source (46) is also described. A laryngoscope having a transducer
mounted to or incorporated on the handle is also described.
Inventors: |
Dey, Philip; (Kingswood,
AU) ; Klineberg, Peter; (Castle Hill, AU) ;
Stokan, Murray; (Winston Hills, AU) |
Correspondence
Address: |
COHEN, PONTANI, LIEBERMAN & PAVANE
Suite 1210
551 Fifth Avenue
New York
NY
10176
US
|
Assignee: |
Western Sydney Area Health Service
of Westmead Hospital, Techmin Pty Ltd
|
Family ID: |
25646617 |
Appl. No.: |
11/105240 |
Filed: |
April 13, 2005 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11105240 |
Apr 13, 2005 |
|
|
|
10471977 |
Sep 15, 2003 |
|
|
|
10471977 |
Sep 15, 2003 |
|
|
|
PCT/AU02/00278 |
Mar 12, 2002 |
|
|
|
Current U.S.
Class: |
600/179 ;
600/191; 600/199 |
Current CPC
Class: |
A61B 1/00055 20130101;
A61B 1/0676 20130101; A61B 1/0684 20130101; A61B 1/00034 20130101;
A61B 2562/043 20130101; A61B 1/267 20130101; A61B 2562/0247
20130101 |
Class at
Publication: |
600/179 ;
600/199; 600/191 |
International
Class: |
A61B 001/06; A61B
001/267 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 14, 2001 |
AU |
PR3725 |
Nov 6, 2001 |
AU |
PR8696 |
Claims
1. An endoscope for insertion in a body cavity or orifice and
having at least one light source mounted thereon for providing
illumination of the cavity or orifice, the endoscope being
characterized in that the light source is a light emitting
diode.
2. An endoscope in accordance with claim 1, hereof wherein the
endoscope is a laryngoscope comprising a handle and a disposable
blade, the blade being removably the attached to the handle.
3. An endoscope in accordance with claim 1, hereof wherein the
endoscope is a laryngoscope having a handle and a disposable blade;
one or more light radiating devices being mounted on the blade of
the laryngoscope.
4. An endoscope in accordance with claim 1, hereof wherein the
endoscope is a laryngoscope having a handle and a disposable blade
characterised in that the LED is mounted to the handle of the
laryngoscope.
5. An endoscope in accordance with claim 1, hereof wherein the
endoscope is a laryngoscope having a handle and a disposable blade
characterized in that the LED is mounted to the handle of the
laryngoscope and the blade has a light transfer conduit adapted to
transfer light emitted by the LED from its position on the handle
along at least a portion of the blade to one or more light
radiating devices on the blade.
6. An endoscope in accordance with claim 1, hereof wherein the
endoscope is a laryngoscope having a handle and a disposable blade
characterised in that the LED is mounted to the handle of the
laryngoscope and the blade has a light transfer conduit adapted to
transfer light emitted by the LED from a first end at or adjacent a
proximal end of the blade to a second end positioned on the blade
at a location distal the proximal end of the blade.
7. An endoscope in accordance with claim 1, hereof wherein the
endoscope is a laryngoscope having a handle and a disposable blade
characterised in that the LED is mounted to the handle of the
laryngoscope and the blade has an acrylic cylindrical light
transfer tube adapted to transfer light emitted by the LED from a
first end at or adjacent a proximal end of the blade to one or more
light radiating devices at a second end positioned on the blade at
a location distal the proximal end of the blade.
8. An endoscope in accordance with claim 1, hereof wherein the
endoscope is a laryngoscope comprising a handle and a disposable
blade, the blade being removably the attached to the handle and the
LED being activated when the blade is mounted to the handle and
deactivated when the blade is removed from the handle.
9. An endoscope in accordance with claim 1, hereof wherein the
endoscope is a laryngoscope having a handle and a disposable blade
characterized in that the LED is mounted to the handle of the
laryngoscope and the blade has a light transfer conduit adapted to
transfer light emitted by the LED from its position on the handle
along at least a portion of the blade to one or more light
radiating devices on the blade there being a switch to ensure that
the LED remains illuminated while the blade is attached to the
handle but that the LED is extinguished upon removal of the blade
from handle; the switch utilizing an induction coil mounted on the
handle and a coil or other component capable of carrying an induced
electrical current on the blade; the induction coil on the handle
and the coil or other component on the blade interacting such that
modification in current flowing through the coil on the handle
caused by proximity of the induction coil or other component on the
blade is detected by circuitry in the handle which modifies the on
off state of the LED; none of the components of the switch having
exposed contacts or moving parts external to the handle.
10. An endoscope in accordance with claim 1, hereof wherein the
endoscope is a laryngoscope having a handle and a disposable blade
characterized in that the LED is mounted to the handle of the
laryngoscope and the blade has a light transfer conduit adapted to
transfer light emitted by the LED from its position on the handle
along at least a portion of the blade to one or more light
radiating devices on the blade there being a switch to ensure that
the LED remains illuminated while the blade is attached to the
handle but that the LED is extinguished upon removal of the blade
from handle; the switch utilizing an induction coil mounted on the
handle and a coil or other component capable of carrying an induced
electrical current on the blade; the induction coil on the handle
and the coil or other component on the blade interacting such that
modification in current flowing through the coil on the handle
caused by proximity of the induction coil or other component on the
blade is detected by circuitry in the handle which modifies the on
off state of the LED; none of the components off the switch having
exposed contacts or moving parts external to the handle; the coil
in the handle and the coil in the blade being comprised of at least
two turns of electrically conductive wire and the coil in the
handle being tuned to parallel resonance by a capacitor.
11. An endoscope in accordance with claim 1, hereof wherein the
endoscope is a laryngoscope having a handle and a disposable blade
characterised in that the LED is mounted to the handle of the
laryngoscope and the blade has a light transfer conduit adapted to
transfer light emitted by the LED from its position on the handle
along at least a portion of the blade to one or more light
radiating devices on the blade there being a switch to ensure that
the LED remains illuminated while the blade is attached to the
handle but that the LED is extinguished upon removal of the blade
from handle; the switch utilizing an induction coil mounted on the
handle and a coil or other component capable of carrying an induced
electrical current on the blade; the induction coil on the handle
and the coil or other component on the blade interacting such that
modification in current flowing through the coil on the handle
caused by proximity of the induction coil or other component on the
blade is detected by circuitry in the handle which modifies the on
off state of the LED; none of the components off the switch having
exposed contacts or moving parts external to the handle; the
induction coil in the handle being capable of serving the
additional function of inductively charging a rechargeable battery
stored within the handle of the device when brought into proximity
with a complimentary charger adapted to receive the handle.
12. An endoscope in accordance with claim 1, hereof wherein the
endoscope is a laryngoscope having a disposable handle and a blade
characterized in that the LED is mounted to the handle of the
laryngoscope and the blade has a light transfer conduit adapted to
transfer light emitted by the LED from its position on the handle
along at least a portion of the blade to one or more light
radiating devices on the blade there being a switch to ensure that
the LED remains illuminated while the blade is attached to the
handle but that the LED is extinguished upon removal of the blade
from handle; the switch utilizing an induction coil mounted on the
handle and a coil or other component capable of carrying an induced
electrical current on the blade; the induction coil on the handle
and the coil or other component on the blade interacting such that
modification in current flowing through the coil on the handle
caused by proximity of the induction coil or other component on the
blade is detected by circuitry in the handle which modifies the on
off state of the LED; none of the components of the switch having
exposed contacts or moving parts external to the handle; a pressure
sensing switch on the blade adapted to be activated by excessive
pressure between the blade and teeth of a patient; the induction
coil in the handle being capable of serving the additional function
of transferring signals from the pressure sensing switch on the
blade to electronic alarm components in the handle.
13. A method of intubating a patient comprising the step of using
an endoscope and accordance with claim 1 hereof.
Description
[0001] This application is a continuation of U.S. patent
application Ser. No. 10/471,977 which was filed with the U.S.
Patent and Trademark Office on Sep. 15, 2003 which is a U.S.
National Stage of application No. PCT/AU02/00278, filed on Mar. 12,
2002. Priority is claimed on that application and on the following
application(s): Country: Australia, Application No. PR3725, Filed:
Mar. 14, 2001; Country: Australia, Application No.: PR8696, Filed:
Nov. 6, 2001.
FIELD OF THE INVENTION
[0002] The present invention relates to a pressure sensor and in
particular to a pressure sensor for detecting pressure applied to a
patient's teeth during use of a laryngoscope. The present invention
also relates to a laryngoscope having a light source mounted
thereon.
BACKGROUND OF THE INVENTION
[0003] Laryngoscopes are used by physicians, in particular
anaesthetists, to perform laryngoscopy and visualise the larynx.
Once in place, the anaesthetist can more readily insert
endotracheal tubes and the like into the trachea of the patient.
The design of laryngoscopes has been relatively unchanged for many
decades, with the scope normally comprising a handle and a
detachably mounted hook-on blade which are connected together in a
substantially L-shaped configuration.
[0004] Dental trauma during laryngoscopy is a relatively common
complication. Such dental trauma normally results from excess
pressure being applied to the upper front teeth of the patient,
which can act as a fulcrum.
[0005] While learning laryngoscopy it is difficult for the trainee
and supervisor to estimate how much pressure is being applied to
the maxillary incisors. During difficult intubations, even
experienced laryngoscopists can apply excessive force.
[0006] While larynoscopes having pressure sensors have been
described in the patent literature (eg. U.S. Pat. No. 5,536,245),
such sensors have not been seen in use by the present inventors.
This is postulated by the present inventors to be due to
complications in the manufacture and/or use of hitherto known
designs.
[0007] The present application is directed to a pressure sensor
that can be used with or on a laryngoscope that addresses the
perceived complications in the art.
[0008] During visual examination, a light bulb mounted on the scope
can be illuminated to assist in illuminating the area being
examined by the anaesthetist or surgeon during use. Such bulbs have
typically comprised an incandescent bulb drawing power from one or
more batteries mounted in the handle of the scope.
[0009] Due to concerns raised by the possibility of
cross-contamination arising from the use of larnygoscopes on
different patients, larynoscope blades are now routinely sterilised
following use on a single patient. Larnygoscope handles are also
routinely decontaminated by being wiped with a bactericidal
solution. This requirement has significantly increased the stock of
laryngoscope blades and handles that must be held in store by any
one hospital. Following repeated sterilisations, the performance of
the laryngoscope also decreases eventually to the point where it
must be discarded. Enquiries by the present inventors have
determined that light bulbs mounted on larnyngoscope do not
typically last more than three to five sterilisations of the device
and must, therefore, be routinely replaced. This requirement to
purchase, sterilise, store and continually replace light bulbs on
laryngoscopes represents a significant cost for a busy hospital or
other medical facility.
[0010] The present application is directed to a laryngoscope that
addresses the perceived complications in the art.
[0011] Any discussion of documents, acts, materials, devices,
articles or the like which has been included in the present
specification is solely for the purpose of providing a context for
the present invention. It is not to be taken as an admission that
any or all of these matters form part of the prior art base or were
common general knowledge in the field relevant to the present
invention as it existed in Australia before the priority date of
each claim of this application.
SUMMARY OF THE INVENTION
[0012] Throughout this specification the word "comprise", or
variations such as "comprises" or "comprising", will be understood
to imply the inclusion of a stated element, integer or step, or
group of elements, integers or steps, but not the exclusion of any
other element, integer or step, or group of elements, integers or
steps.
[0013] According to a first aspect, the present application is
directed to a first invention comprising a laryngoscope comprising
a blade and handle, a transducer being attached to the blade, the
transducer comprising a circuit having a switch means and an
indicator means, the switch means comprising a layer of an
electrically conductive polymeric material that is deformable into
contact with an electrically conductive contact of the circuit, on
presence of a predetermined level of incident pressure, to complete
the circuit and so activate the indicator means.
[0014] In this aspect, the block of electrically conductive
polymeric material is preferably formed from a carbon-loaded
silicone rubber. The block preferably has an underside having at
least one channel formed therein, each of said at least one channel
overlaying a respective one of said electrically conductive
contact, the channel being deformable on presence of said
predetermined incident pressure into contact with said contact.
[0015] Each of said at least one contact can comprise a metal track
formed on a printed circuit board. The metal tracks can comprise
part of the circuit that is closed when the block contacts the
track so as to allow power to activate the indicator means.
[0016] In this aspect, the indicator means preferably comprises an
alarm means actuable on closure of the circuit. The alarm means
preferably comprises a visual means and/or an audible means.
[0017] The visual means can comprise one or more lights or light
emitting diodes (LED). In another embodiment, the visual means can
comprise a readout giving a measure of relative or absolute
pressure detected by the transducer. The audible means can comprise
a buzzer, bell or the like. The frequency and/or volume of the
buzzer can vary in response to changes in incident pressure
measured by the transducer. For example, the frequency and/or
volume of the buzzer can increase in response to increasing
pressure.
[0018] According to a second aspect, the present invention is
directed to a second invention comprising a sensing means
comprising a transducer adapted to be mounted to a blade of a
laryngoscope, and an indicator means, the transducer comprising at
least a layer of a polymeric material that undergoes a change in
resistivity in response to incident pressure thereon, the change in
resistivity being useable by the indicator means to provide an
output at least indicative of the incident pressure.
[0019] According to a third aspect, the present invention is
directed to a third invention comprising a laryngoscope comprising
a blade and handle, a transducer being attached to the blade, and
an indicator means, the transducer comprising at least a layer of a
polymeric material that undergoes a change in resistivity in
response to incident pressure thereon, the change in resistivity
being useable by the indicator means to provide an output at least
indicative of the incident pressure.
[0020] In one embodiment of the above aspects, the transducer can
be formed at least in part of a material that permanently deforms
on contact with the teeth of a patient. The degree of permanent
deformation of the material of the transducer is preferably
proportional to the degree of pressure applied to the transducer by
the teeth of the patient. In one embodiment, the permanent
deformation comprises depression of said material in the region of
contact between the transducer and the teeth of the patient. In
this embodiment, the depth of a depression is indicative of the
degree of pressure applied to the teeth of the patient, with the
deeper the depression, the greater the applied pressure.
[0021] According to a fourth aspect, the present invention is
directed to a fourth invention comprising a sensing means adapted
to be attached to a blade of a laryngoscope, and an indicator means
adapted to output at least a relative determination of incident
pressure detected by the transducer, the transducer being formed at
least in part of a material that permanently deforms on contact
with the teeth of a patient.
[0022] In a preferred embodiment of the fourth aspect, the degree
of permanent deformation of said material is proportional to the
degree of pressure applied to the transducer by the teeth of the
patient. In one embodiment, the permanent deformation comprises
depression of said material in the region of contact between the
transducer and the teeth of the patient. In this embodiment, the
depth of a depression is indicative of the degree of pressure
applied to the teeth of the patient, with the deeper the
depression, the greater the applied pressure.
[0023] In one embodiment of the second and fourth aspects, a
plurality of transducers can be packaged together. For example, a
plurality of transducers can be mounted by a release adhesive to a
common backing layer. When required, a transducer can be peeled
from the backing layer, used, and then discarded.
[0024] In the second and third aspects, the polymeric material
comprising the transducer can be one or more layers of the
polymeric material sold under the name Velostat.TM. by the company
3M.TM., ie. a carbon impregnated polyolefin. Other materials having
equivalent or similar properties can also be utilised. The
electrical resistivity of the material is preferably inversely
proportional to incident pressure, the incident pressure causing
compression in at least a region of the transducer.
[0025] The layer of Velostat.TM. is preferably sandwiched between
respective layers of an electrically conductive material. Each
sandwich layer is preferably formed from the same material. The
sandwich layers can be maintained in a substantially parallel
spaced relationship by the layer of Velostat.TM.. The electrically
conductive material can be a metal, such as copper sheet. The
sandwich layers act as respective electrodes for the transducer. In
a preferred embodiment, the sandwich layers can act as the material
that permanently deforms on contact with the teeth of a
patient.
[0026] The transducer can further include a layer of relatively
resiliently flexible material mounted to at least one face thereof.
This layer can be selected from the group comprising a foam, an
elastomeric material and a polymeric material.
[0027] The resiliently flexible material layer can have a layer of
adhesive on one or both faces. The face of the layer that becomes
the inwardly facing layer following mounting of the transducer
preferably has a removable backing layer over the adhesive. The
backing layer of the adhesive is preferably removed to allow
mounting of the transducer to the blade of the laryngoscope.
[0028] The transducer further preferably includes a protective
layer on at least one face of the transducer. The protective layer
is preferably relatively electrically insulating. The layer is
preferably transparent to allow viewing of the electrically
conductive layer therebeneath. A layer of adhesive can be used to
bond the protective layer to the transducer.
[0029] Electrically conducting wires are preferably electrically
connected to each of the electrodes of the transducer. The wires
preferably are used to provide electrical connection between the
transducer and the indicator means. The wires are preferably formed
from a metallic material, such as copper or aluminium wire. Each of
the wires is preferably surrounded by an electrically insulating
material for a majority of its length. The electrical insulation is
preferably removed where the wire comes into contact with its
respective electrode and where it makes electrical connection to
the indicator means.
[0030] The wires are preferably connected to each of the electrodes
using electrically conductive adhesive tape or an electrically
conductive adhesive epoxy. Other suitable bonding techniques,
including crimping and soldering can be envisaged.
[0031] The indicator means preferably comprises an electrical
circuit. The transducer is preferably a component of the electrical
circuit. The electrical circuit preferably uses a voltage
comparator to detect the change in resistance of the transducer in
response to incident pressure. Where the transducer has a layer
that decreases in electrical resistivity in response to an increase
in incident pressure and vice versa, the circuit preferably notes
the change in resistance. When the resistance drops to or below a
predetermined threshold, the circuit preferably activates an alarm
means that is part of the circuit.
[0032] The alarm means can comprise a visual means and/or an
audible means. The visual means can comprise one or more lights or
light emitting diodes (LED). In another embodiment, the visual
means can comprise a readout giving a measure of relative or
absolute pressure detected by the transducer. The audible means can
comprise a buzzer, bell or the like. The frequency and/or volume of
the buzzer can vary in response to changes in incident pressure
measured by the transducer. For example, the frequency and/or
volume of the buzzer can increase in response to increasing
pressure.
[0033] The electrical circuitry of all of the aspects can be
powered by a power source, such as one or more batteries or mains
power. The circuitry can include a light or light emitting diode
(LED) that indicates the operational status of the circuit (eg.
On/Off). This light or LED can be a different colour or multicolour
to that used as the visual means.
[0034] Where the circuitry relies upon the exceeding of a
predetermined threshold, the threshold for activation of the alarm
means can be variable and can be set by the user prior to use or
even adjusted during use. In certain instances, such as where
intubation is being carried out by trainees, the threshold may be
set relatively low to ensure that the alarm means, for example, is
activated in response to a relatively small incident pressure being
applied to the patient's teeth during use. As the user becomes more
experienced with the use of a laryngoscope, the threshold can be
increased such that the alarm means only operates in instances
where relatively excessive pressure is being applied to the teeth
of the patient.
[0035] In a still further embodiment, the circuit of any of the
above aspects can include a memory means to allow recording of
pressure data measured by the transducer. The memory means can
preferably automatically, or on request, transmit the recorded data
to a playback means such as a personal computer, printer or monitor
to allow visualisation of the pressure readings over time.
[0036] The transducer is preferably not removable from the blade of
the laryngoscope. The blade, including the transducer, is further
preferably disposable.
[0037] The blade with the transducer mounted thereon is preferably
packaged in a sterile container following manufacture and is
sterile when removed from the package and mounted to the
laryngoscope handle.
[0038] In a further embodiment of the above aspects, a light
source, such as a high intensity light emitting diode (LED) can be
mounted to the transducer. The LED can be mounted to the distal end
of the transducer and so provide illumination of the larynx during
use.
[0039] According to a fifth aspect, the present invention is
directed to a fifth invention comprising a method of intubating a
patient comprising at least the steps of:
[0040] using a laryngoscope having a sensing means, according to
the above aspects; and
[0041] using the indicator means to monitor the pressure applied to
the teeth of the patient during use of the laryngoscope.
[0042] According to a sixth aspect, the present invention is
directed to a sixth invention comprising an endoscope for insertion
in a body cavity or orifice and having at least one light source
mounted thereon for providing illumination of the cavity or
orifice, the endoscope being characterised in that the light source
is a light emitting diode.
[0043] In the sixth aspect, the endoscope can comprise a
laryngoscope. In another embodiment, the endoscope can comprise an
otoscope.
[0044] In one embodiment, the endoscope is disposable after a
single use. In this embodiment, the endoscope is preferably formed
from a plastics material.
[0045] In the sixth aspect, the laryngoscope can comprise a handle
and a blade. The blade can be non-removably attached to the handle
at a first end thereof. In another embodiment, the blade is
removably attachable to the handle. The blade preferably has a
proximal end and a distal end with its proximal end attachable to
the handle. The orientation of the blade to the handle can be
fixed. Alternatively, the blade orientation can be adjustable.
[0046] In one embodiment of the sixth aspect, the light emitting
diode (LED) can comprise a gallium arsenide (GaAs) LED. Other
suitable light emitting diodes having suitable luminous intensities
can be utilised. In one embodiment, the luminous intensity is
preferably at least 5600 mcd, more preferably at least 6000 mcd,
and still more preferably at least between 10000 and 15000 mcd.
[0047] In a further embodiment of the sixth aspect, more than one
light source can be mounted to the endoscope.
[0048] In one embodiment, the LED can be mounted to the blade of
the laryngoscope. More preferably, the LED can be mounted to the
handle of the laryngoscope. In this case, the LED is preferably
mounted to the handle at or adjacent its first end. The LED is
preferably non-removably mounted to the handle.
[0049] The blade can include a light transfer means adapted to
transfer light emitted by the LED from its position on the handle
through at least a portion of the blade. In one embodiment, the
light transfer means has a first end at or adjacent the proximal
end of the blade. A second end of the light transfer means is
positioned on the blade at a location distal the proximal end of
the blade. The second end of the light transfer means may be at or
adjacent the distal end of the blade or positioned back along the
blade at a desired distance from its distal end.
[0050] In one embodiment, the light transfer means can comprise a
cylindrical member. Members having other suitable shapes can be
envisaged. The member is preferably straight, however, non-straight
members could be utilised. In one embodiment, the member can be
formed from an acrylic material. The light transfer means
preferably serves to direct the light emitted from the LED through
the blade and out into the body cavity or orifice into which the
laryngoscope has been inserted.
[0051] In a still further embodiment, the endoscope can incorporate
a switching means for use in activating and/or deactivating the
light source. In one embodiment, the switching means can be
operable by a user of the endoscope.
[0052] In a more preferred embodiment of the laryngoscope, the LED
is preferably activated when the blade is mounted to the handle. In
this case, the LED preferably remains illuminated while the blade
is attached to the handle. The LED preferably switches off on
removal of the blade from the handle.
[0053] In this case, the switching means can comprise an actuable
member mounted on the handle that is activated by a complementary
actuating member on mounting of the blade to the handle. For
example, the handle and blade can have complementary bayonet type
fittings to allow the blade to be attached to the handle.
[0054] In another embodiment of the sixth aspect, the switching
means can utilise an induction coil mounted within the handle. The
blade can also incorporate a coil or magnetic component. On
attachment of the blade to the handle, the current flowing through
the coil in the handle is modified. This modification can be
detected by circuitry in the handle and lead to illumination of the
light source.
[0055] The coil in the handle and the blade, can be comprised of at
least two turns of electrically conductive wire. The coil in the
handle is preferably tuned to parallel resonance by a capacitor
that is part of the circuitry.
[0056] The induction coil in the handle can also preferably be used
as a means of inductively charging the batteries stored within the
handle of the device. A charger can receive the handle and
inductively charge the batteries within the handle. Each charger
can preferably be used to charge more than one handle.
[0057] The inductive coupling between the handle and the coil can
also act as a means of transferring signals from the transducer,
when present, to the circuit, when the circuit is located within
the handle.
[0058] The handle can have a cavity for containing the circuitry
for operation of the light source as defined above. The power
source for the light source and circuitry is also preferably housed
within the cavity. The power source preferably comprises one or
more batteries. Each battery is preferably non-removable from the
handle. The batteries can also be rechargeable to allow re-use of
the batteries. The handle is preferably sealed to prevent fluid
ingress therein.
[0059] According to a seventh aspect, the present invention is
directed to a seventh invention comprising a method of intubating a
patient comprising the step of using the laryngoscope as defined
herein as the sixth aspect of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0060] By way of example only, preferred embodiments of the
invention are now described with reference to the accompanying
drawings, in which:
[0061] FIG. 1 is a simplified side elevation view of one embodiment
of a transducer according to the present invention;
[0062] FIG. 2 is a schematic view of one embodiment of a transducer
and indicator means according to the present invention;
[0063] FIG. 3 is a depiction of a patient undergoing laryngoscopy
using a laryngoscope having a transducer according to the present
invention removably attached thereto;
[0064] FIG. 4 is a depiction of a patient undergoing laryngoscopy
using a laryngoscope having a light emitting diode (LED) mounted
thereon;
[0065] FIG. 5 is a cut-away perspective view of the handle and
blade of the laryngoscope;
[0066] FIG. 6 is another cut-away perspective view of the
laryngoscope of FIG. 5;
[0067] FIGS. 7a-7c are various perspective views of the
laryngoscope blade; and
[0068] FIGS. 8a and 8b are side elevational and inverse plan views
of a block of material for use as part of a switch for another
embodiment of a sensing means according to the present
invention.
PREFERRED MODE OF CARRYING OUT THE INVENTION
[0069] One embodiment of a sensing means having a transducer
according to the present invention is generally depicted as 10 in
FIGS. 1 to 3.
[0070] As depicted in FIG. 3, the transducer 10 is adapted to be
removably adhered to a blade 41 of a laryngoscope 40. While the
depicted transducer can be removably attached to the blade 41, it
should be appreciated that a laryngoscope having a non-removable
transducer attached thereto is also encompassed within the scope of
the present invention.
[0071] The device further includes an indicator device depicted
schematically as 11 in FIG. 2 which is described in more detail
below.
[0072] In the depicted embodiment, the transducer 10 is formed of a
layer of polymeric material 12 sold under the name Velostat.TM. by
the company 3M.TM., ie. a carbon impregnated polyolefin. The
electrical resistivity of this layer 12 is inversely proportional
to incident pressure, the incident pressure causing compression in
at least a region of the transducer 10.
[0073] The layer 12 of Velostat.TM. is sandwiched between
respective copper electrodes 13 that are maintained in a
substantially parallel spaced relationship by the layer 12 of
Velostat.TM.. While copper electrodes are preferred due to the
permanent deformation suffered by the material on being brought
into contact with the patient's teeth, other electrically
conductive materials could be utilised.
[0074] As depicted, the transducer 10 can further include a layer
14 of relatively resiliently flexible material mounted to at least
one face thereof. Layer 14 can be selected from the group
comprising a foam, an elastomeric material and a polymeric
material.
[0075] The resiliently flexible material layer 14 can have a layer
of adhesive on one or both of its faces. The face 15 of the layer
14 that becomes the inwardly facing layer following mounting of the
transducer 10 the blade 41 preferably has a removable backing layer
(not depicted) over the adhesive.
[0076] The transducer 10 further has a protective layer 16 on what
becomes its outward face. The depicted protective layer 16 is
relatively electrically insulating and transparent to allow viewing
of the electrode 13 therebeneath. A layer of adhesive can be used
to bond the protective layer 16 to the electrode 13.
[0077] The depicted transducer 10 is packaged in a sterile
container following manufacture and should be sterile when removed
from the package and mounted to the laryngoscope blade 41. A
plurality of transducers 10 can be packaged together and delivered
ready for individual use. For example, while not depicted, a
plurality of transducers 10 can be mounted by a release adhesive to
a common backing layer. When required, a transducer can be peeled
from the backing layer, used, and then discarded.
[0078] Electrically conducting wires 17 are connected to each of
the electrodes 13 of the transducer 10. The wires 17 provide
electrical connection between the transducer 10 and the indicator
device 11.
[0079] The depicted wires 17 are connected to each of the
electrodes 13 using electrically conductive adhesive tape or an
electrically conductive adhesive epoxy. Other suitable bonding
techniques, including crimping and soldering can be envisaged.
[0080] The indicator device 11 comprises an electrical circuit. The
transducer 10 is a component of this electrical circuit. The
depicted indicator device 11 uses a voltage comparator to detect
the change in resistance of the transducer 10 in response to
incident pressure. As the layer 12 decreases in electrical
resistivity in response to an increase in incident pressure and
vice versa, the circuit detects the change in resistance. When the
resistance drops to or below a predetermined threshold, the circuit
activates a buzzer and/or illuminates a light emitting diode
mounted in the indicator device 11.
[0081] While not depicted, the indicator device can include a
readout giving a measure of relative or absolute pressure detected
by the transducer 10. The frequency and/or volume of the buzzer
varies in response to changes in incident pressure measured by the
transducer. In this example, the frequency and/or volume of the
buzzer increases in response to increasing pressure.
[0082] The electrical circuitry of the depicted indicator device 11
is powered by one or more batteries. The circuitry includes an LED
that indicates the operational status of the circuit (eg. On/Off).
This LED is a different colour to that described above. The
indicator device also includes an On/Off switch that allows a user
to connect/disconnect power to the circuitry when desired.
[0083] The threshold of the circuitry is variable and can be set by
the user prior to use or even adjusted during use. In certain
instances, such as where intubation is being carried out by
trainees, the threshold may be set relatively low to ensure that
the indicator means operates in response to the pressure being
applied to the patient's teeth during use. As the user becomes more
experienced with the use of a laryngoscope, the threshold can be
increased such that it only operates in instances where relatively
excessive pressure is being applied to the teeth of the
patient.
[0084] In use, the transducer 10 will firstly be removed from its
sterile packaging and adhered to the blade 41 as depicted in FIG.
3. The wires 17 can then be electrically connected to the indicator
device 11.
[0085] During use, any pressure applied to the patient's teeth by
the blade 41 is detected by the transducer 10. The circuitry within
the indicator device 11 can be set such that the LED and/or buzzer
of the indicator device 11 only activates when a certain threshold
is reached.
[0086] Following completion of the laryngoscopy, the blade 41 is
removed from the mouth. The transducer 10 can then be peeled from
the blade 41 and discarded.
[0087] FIGS. 8a and 8b depict an alternative component for use as a
switch for activating the indicator means 11. The component
comprises a block 60 of an extrinsically conductive material,
namely a carbon-loaded silicone rubber. The block 60 has a
plurality of channels 61 formed in the underside thereof. On the
occurrence of an incident pressure on the top side 62 of the block
60, one or more of the channels will deform sufficiently to bring
at least a portion of the block into contact with a metal track of
a printed circuit board that can pass therebeneath (not
depicted).
[0088] The block 60 and metal track act together as a switch to
control the supply of a power to an indicator means 11 used in
association with the switch. When one or more of the channels 61
collapse, the circuit is closed and power is provided to the
indicator means 11 so activating an alarm means, such as a buzzer
and/or light.
[0089] FIG. 4 depicts another embodiment of a laryngoscope
according to the present invention that can be used by physicians,
in particular anaesthetists, to perform laryngoscopy and visualise
the larynx. Once in place, the anaesthetist can more readily insert
endotracheal tubes and the like into the trachea of the
patient.
[0090] The laryngoscope according to the present invention is
generally depicted as 40 in FIGS. 4-7c.
[0091] The laryngoscope 40 depicted in FIG. 4 is disposable and
comprises a handle 42 and a blade 41. In this embodiment, both the
handle 42 and blade 41 are formed from a plastics material.
Suitable materials include polycarbonate, or a copolymer from the
ABS (acrylonitrile-butadiene-styre- ne) family.
[0092] The depicted blade 41 is removably attachable to the handle
42 through a bayonet fitting 43. The blade 41 has a proximal end 44
and a distal end 45 with its proximal end 44 attachable to the
handle 42. In the depicted embodiment, the orientation of the blade
41 to the handle 42 once attached is fixed. In another embodiment,
the blade 41 could be constructed so as to be adjustable relative
to the handle 42.
[0093] The laryngoscope 40 has a light source 46 mounted thereon
for providing illumination of the cavity or orifice, during use.
The light source 46 comprises a high intensity gallium arsenide
(GaAs) light emitting diode (LED) supplied by Nichia Corporation of
Tokushima 774-8601, Japan. Other suitable light emitting diodes
having suitable luminous intensities, including LEDs from other
suppliers can be utilised.
[0094] In the depicted embodiment, the LED 46 is non-removably
mounted to the handle 42 of the laryngoscope 40.
[0095] The blade 41 has a straight cylindrical acrylic light pipe
47 incorporated therein that transfers light emitted by the LED 46
from its position on the handle 42 through the blade 41 to an
outlet 48. The light pipe 47 serves to direct the light emitted
from the LED 46 through the blade 41 and out into the body cavity
or orifice into which the laryngoscope 40 has been inserted.
[0096] The laryngoscope incorporates a switching means for use in
activating and/or deactivating the LED 46. In this embodiment, the
LED 46 is activated when the blade 41 is mounted to the handle 42
and remains illuminated while ever the blade 41 is attached to the
handle 42.
[0097] The handle 42 has a cavity 49 for containing the circuitry
51 for operation of the LED 46 as defined above. The power source
for the LED and circuitry 51 is also housed within the cavity 49
and comprises a series of batteries 52. The batteries 52 in the
depicted embodiment are not removable from the handle 42. They are,
however, rechargeable to allow re-use of the handle in association
with a blade.
[0098] In a typical use, a new blade 41 will be removed from
sterile packaging and attached to a handle 42. On attachment, the
LED 46 will illuminate and the laryngoscope 40 can be used and
positioned by the anaesthetist as depicted in FIG. 4. Following
use, the blade 41 can be removed from the handle 42 and disposed
of. As, in the depicted embodiment, there is either no or minimal
circuitry or wires mounted within the blade 41, the blade 41 is
readily disposable at minimum cost. It will be appreciated that in
another embodiment, the blade 41 could incorporate other features,
including circuitry and other devices, if desired. If necessary,
the handle 42 can be sterilised ready for re-use with a new blade
41 when required.
[0099] It will be appreciated by persons skilled in the art that
numerous variations and/or modifications may be made to the
invention as shown in the specific embodiments without departing
from the spirit or scope of the invention as broadly described. The
present embodiments are, therefore, to be considered in all
respects as illustrative and not restrictive.
* * * * *